Problem Cold start alfa romeo 166 2.0TS


My problem is when I start the car.. when cold, the idle stutters but recovers... + if I accelerate it when cold it gives me misses.. until about 3000 laps.
When it heats up..that is, over 50..60 degrees, I can start from the spot with it..but after 3000 laps, it has no throttle at all..out of 155 horses, it seems that there are only 100 left.
I specify that I changed the fuel pump... spark plugs, plugs, coils, cleaned the injectors... .